Nb3Sn-composite conductors with Aluminum as electrical stabilizer and stainless steel as mechanical reinforcement

Three-component conductors composed of a preheat-treated Nb3Sn flat cable, aluminium, and stainless steel were soldered together in a straight alignment and then wound in a single-layer coil with a diameter of 90 mm. The performance of the composite conductor was determined mainly by the position of the steel, because the steel shifts the neutral plane considerably due to its high modulus of elasticity and can generate high compressive forces on the Nb3Sn with a consequent reduction of critical current density. The aluminum stabilizer developed its full stabilizing performance only in close contact with the superconductor, because resistive layers between them cause partial resistivity in the superconductor.